As Peatlands Thaw, Two Gases Much Worse Than Carbon Are Being Unchained

Thawing of permafrost peatlands of the Arctic could release so much methane and nitrous oxide that our planet might never recover. These permanently frozen areas cover 625,000 square miles around the Arctic Circle--and as you read this, they are melting.

 

Without intervention to prevent it, dozens of billions of tons of carbon will be released by 2100 as the permafrost peatlands thaw and the plant materials become subjected to microbial breakdown.

 

Although carbon dioxide is the better-known greenhouse gas, methane is up to 30 times as potent in terms of the heat trapping that powers global warming. And nitrous oxide leaves both in the dust: A single molecule of nitrous oxide has the warming potential of 300 molecules of carbon dioxide.

 

Permafrost peatlands are formed as eons of dead vegetation accumulate. The dead plant material, peat, mixes with water to form a kind of slurry--and when the slurry freezes it becomes a permafrost peatland. When frozen, the organic material ceases to decompose.

 

About 20% of all permafrost areas on earth are peat-based, but when a peat area thaws, bacteria go to work, and it releases five times as much carbon into the air as mineral-based soils.

 

Current thinking suggests that as the permanently frozen peat thaws, microbial action will work on the dead organic matter. Is it this area that most of the methane will come from? Perhaps most of the methane comes when new plants on the surface die and decompose.

 

Knowing where the methane comes from is key to getting a hold on managing climate change.

 

Researchers conducted studies near Teslin in the Yukon Territory and near Yellowknife in the Northwest Territories. They took peat cores from formerly permafrost areas and conducted radiocarbon studies. The percent of 14C in released methane or carbon dioxide is different in the old peat than in new vegetation, so it is possible to determine what percent of the methane comes from the thawed portion and what comes from the new growth.